Agitator



March 1956 TAHIKO HONJO ETAL 3,241,606;

AGITA'IOR 8 Sheets-Sheet 2 Filed Aug. 13, 1963 INVENTOR.

March 1966 TAHIKO HONJO ETAL AGITATOR Filed Aug. 13, 1963 8 Sheets-Sheet 3 Wad IN V EN TOR.

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March 1955 TAHIKO HONJO ETAL 3,241,605

AGITAI'OR Filed Aug. 15, 1963 8 Sheets-Sheet 4.

IN V EN TOR.

BY QWWM 0 5 6 MT ffimifm March 22, 1966 TAHlKO HONJO ETAL 3,241,606

AGITATOR 8 Sheets-Sheet 5 Filed Aug. 13, 1963 IN VEN TOR.

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March 1956 TAHIKO HONJO ETAL 3,241,606

AGI'I'ATOR 8 Sheets-Sheet 6 INVENTOR.

Filed Aug. 15, 1963 March 1965 TAHIKO HONJO ETAL 3,241,605

8 Sheets-Sheet '7 Filed Aug. 15, 1963 INVENTOR.

March 22, 1966 TAHIKO HQNJO L 3,241,606

AGITATOR 8 Sheets-Sheet 8 Filed Aug. 15, 1963 W5 I I IN VEN TOR.

BY 5w WM United States Patent 3,241,606 AGITATUR Tahiko Honjo and Mitsugu Mamiya, Osaka, Japan, as signors to The Shionogi 8: Co., Ltd, Osaka, Japan, a corporation of Japan Filed Aug. 13, 1963, Ser. No. 301,851 Claims priority, application Japan, Aug. 16, 1962, 37/ 35,522 4 Claims. (Cl. 165-86) The present invention relates to agitators, and more particularly to an agitator which effectively achieves fluid-agitating and at the same time heat exchanging purposes.

It is often required in chemical industry to cool a liquid in process, and conventionally, agitating vessels are provided with cooling coils around the inner walls or cooling jackets around the outer walls. However, cooling coils around the inner wall of the agitating vessel interfere with good delivery and drainage of liquid processed in it especially when the liquid is viscous or further crys tallized. On the other hand, a cooling jacket around the outer wall of an agitating vessel will naturally be low in heat transfer coefficient. And both of the cooling devices described above cannot be expected to lower the temperature rapidly enough to avoid undesirable secondary reactions around the agitating blades where the maximum heat may often be caused in an acute chemical reaction. The present invention has overcome the above described defects of conventional agitators in combination with heat transfer devices.

A major object of the invention is to provide an agitator which cools liquid rapidly and evenly while agitating it.

Another important object of the invention is to provide an agitator which cools liquid with high efficiency while agitating it, yet so facilitating delivery and drainage of liquid processed in the agitator as to minimize the loss of processed liquid and the maintenance in cleaning the inside of the agitating vessel.

A further object of the invention is to provide an agitator which cools liquid, while agitating it, so rapidly as to avoid secondary reaction around the agitating blades where the maximum heat may be caused in an acute chemical reaction.

A still further object of the invention is to provide an agitator which cools liquid while agitating it without being accompanied with any reduction of agitating effects.

According to the invention, a combined agitator and heat exchanger, comprising tubular blade means, a shaft, connecting means for securing the blade means to the shaft for rotation therewith, driving means for rotating said shaft, a passage through said shaft for supplying a fluid heat exchange medium and a second passage through said shaft for returning said medium, and conduit means connecting said medium supply passage and medium return passage to a source of said heat exchange medium, is characterized by said tubular blade means comprising an annular tube disposed coaxially with said shaft, an outer tube communicating with said return passage and with said annular tube, and an inner tube having nozzles and communicating with said supply passage and with said annular tube through said nozzles.

Other objects and advantages of the present invention will appear from the following description of the representative embodiments shown in the accompanying drawings in which:

FIG. 1 is a front view, with portions shown in vertical section, of an agitator in accordance with the present invention.

FIG. 2 is an enlarged front view, with portions shown in vertical section, of the important part in FIG. 1.

FIG. 3 is a plan view, with portions shown in cross section taken approximately on the line 33 in FIG. 2.

FIGS. 4 to 11 illustrate some other examples of the shaft and blade portion, shown partially, of an agitator in accordance with the invention.

Referring to FIGS. 1 to 3, the vessel for agitating liquid is shown as a tank 11 containing liquid A. The tank 11 is closed with a cover 15, through which extends the agitating shaft shown as comprising an inner vertical shaft 13 and an outer vertical shaft 14 to provide a pair of passages for cooling medium. The upper ends of the agitating shafts 13, 14 communicate with a manifold 31, through which both the passages for cooling medium in the pair of shafts 13, 14 are connected to the cooling plant 43. The inner vertical shaft 13 is held to the outer vertical shaft 14 in co-axially spaced relation by means of stays 57 provided along the inner wall of the shaft 14 at intervals.

The shaft 14 is supported in a gear box 22 by means of bearings 20, 21 and a bevel gear 24 is fixed on the shaft 14. The gear box 22 is mounted firmly on the cover 15 of tank 11 by means of bolts and nuts 23 and connected with the manifold 31 in fixed relation by means of vertical support members, bolts and nuts.

The bevel gear 24 engages with another bevel gear 25 fixed to a shaft 26 supported on the casing of the gear box, and driven by a motor 28 secured to the gear box by means of bolts and nuts 27.

In the agitating blades the outer horizontal tube 16 is made integral with the cooling tube 12 and is positioned on one of the diameters of the circle in which this cooling tube 12 is shaped as shown in FIG. 3. The inner horizontal tube 17 is inserted in the outer horizontal tube 16. Both the ends of the tube 1'7. are provided with nozzles 18, 19 respectively which open within the cooling tube 12 in the opposite directions to each other so that cooling medium jetted out of the nozzles may be circulated in the tube as quickly and efficiently as will be explained afterwards. The lower ends of shafts 13, 14 are fixedly connected with the tubes 17 and 16 respectively at the central portion of the horizontal tubes 16 and 17 in such a manner that the axial center line of the vertical shafts 13, 14 hits the center point of the annular tube 12.

The nozzles 18, 19 open along the axial center line of cooling tube 12, while the outer horizontal tube 16 is connected with inner peripheral portions of the cooling tube 12. The tube 17 is inserted in the tube 16 with a clearance 61 between the said tubes corresponding to the clearance 62 between the shafts 13, 14 for passage of cooling medium. Thus, cooling medium supplied by way of the shaft 13 is passed through the tube 17, jetted out of the nozzles 18, 19, circulated in the cooling tube 12, passed through the clearance 61, and finally, taken back by way of the clearance 62 between the shafts.

As shown in FIG. 2, the upper end of the inner vertical shaft 13 is opened to the upper chamber 29 in the manifold 31 by means of a stuffing box including a packing 32, packing cover 34 and bolts and nuts 36 in a sealed relation, while the upper end of the outer vertical shaft 14 is opened to the lower chamber 30 in the socket joint 31 by means of a stuffing box including a packing 33, packing cover 35 and bolts and nuts 36 in a sealed relation. The upper chamber 29 is provided with a threaded inlet 37, while the lower chamber 30 is provided with an outlet 38. The inlet 37 and the outlet 38 are connected with pipes 41 and 42 by means of threaded coupling joints 39 and 40 respectively.

The pipe 41 is connected to the delivery port 48 of a pump 47 by means of a threaded coupling joint 49. The suction port 51 of the pump 47 and the outlet 50 of the cooling plant 43 are connected by means of a pipe 52 and a pair of threaded coupling joints. The pipe 42 is connected to the intake 45 of the cooling plant 43 by means of a threaded coupling joint 44. Thus, cooling medium coming back by way of the outer vertical shaft 14 is returned through the chamber 30 and the pipe 42 to the cooling plant 43, and then sucked through the pipe 52 to the pump 47, from where it is pressure-fed to the inner vertical shaft 13 through the pipe 41 and the upper chamber 29.

In the operation of the agitator, the liquid A is initially introduced into the tank 11 through a cock 60. And the motor 28 is turned on, so that the outer vertical shaft 14 is rotated together with the inner vertical shaft 13 fixed thereto when driving power is transmitted through the bevels 25 and 26. Thus, the wheel like agitating blade is rotated to agitate the liquid A in the tank 11 Also, the motor 53 is turned on to drive the pump 47. Thus the liquid A is cooled, while being agitated, in the tank 11. When the agitation is over, the liquid A is easily delivered and drained out of the tank 11 through a drain 59 even when it is viscous or crystallized. In the abovedescribed circulation of cooling medium through the agitator in accordance with the present invention, heat transfer coefiicient is sufliciently high mainly because of the following reasons.

One is that heat is transferred at high speed from the liquid A to the cooling medium flowing inside the cooling tube 12, because the liquid A flows at the highest velocity in the pipe 12 equivalent to agitating blades, and because the cooling medium flows at a remarkably high velocity within the tube 12 owing to such a high jet velocity at the nozzles 18, 19, say by far more than a few meters per second on an average in normal operations, and constantly balancing the loss of heat due to friction caused against the inner Wall of cooling tube 12 during the course of circulatin through it. In other words, the agitator in accordance with the present invention has a sufliciently high overall coefficient of heat transfer, say a few thousand kcal./m. /hr./C. in normal operations for the fluid A and the fluid inside the tube with a thin wall between them.

The rate of circulation of said cooling medium in the cooling tube 12 is around ten times as much as the rate at which the cooling medium is discharged from the nozzles 18, 19, since the cooling medium is induced into the tube in a high speed jet stream through the nozzle means. The other reason is that an effective convection of heat is performed within the liquid A, because the liquid A is cooled at the highest rate around the cooling tube 12, that is, around the central portion of tank 11 where the maximum heat may be caused, especially in acute chemical reaction and because the cooled liquid is dispersed to other parts at the highest flow rate due to the fact that the flow rate of liquid A is highest around the cooling tube 12 equivalent to agitating blades.

For the above-given two reasons, the cooling effect can be twice or thrice higher in the agitator of the present invention than conventional-type agitators with jacket. And the cooling effect will be improved further with such modifications of the agitating blade portions as improve the agitating effect, thereby, improve the heat transfer effect within the agitating vessel. Some of these modifications are described in the following paragraphs in reference to FIGS. 4 to 11 where the parts similar to those FIGS. 1 to 3 are numbered same as in FIGS. 1 to 3. A second embodiment of the invention is illustrated in FIG. 4 where a cooling tube 12 is provided with a plurality of blades or fins 71 at regular intervals on the outer wall.

Some other embodiments of the invention are illustrated in FIGS. to 11 where the agitating blade portions are shown in various shapes to improve the agitating effect, thus to improve the cooling effect. Their operations are similar to that in FIGS. 1 to 3.

In FIG. 5, a cooling tube 81 is connected to the lower ends of an inner vertical shaft 13 and an outer vertical shaft 13 and an outer vertical shaft 14 in such a manner as to form a P-letter shape.

In FIG. 6, a cooling tube 91 is provided in a shape of a saddle upside down.

In FIG. 7, a cooling tube 92 is provided in a saddle shape.

In FIG. 8, a cooling tube 93 is provided in an X-letter shape in front view.

In FIG. 9, a pair of cooling tubes 94 and 95 are provided in an X-letter shape in front view.

In FIGS. 10 and 11, a pair of cooling tubes 96 and 97 provide a double loop which is X-shaped in elevation.

It will thus be seen that the agitator in accordance with the present invention cools liquid rapidly and evenly, so facilitates delivery and drainage of liquid processed in the vessel as to minimize the loss of processed liquid and the maintenance in cleaning inside it, cools liquid so rapidly as to prevent secondary reactions around the central portion of vessel where the maximum heat may be caused in acute chemical reaction, and cools liquid without reducing the agitating effect.

Obviously many modifications and variations of the invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A combined agitator and heat exchanger comprising tubular blade means, a shaft, connecting means for securing the blade means to the shaft for rotation therewith, driving means for rotating said shaft, a passage through said shaft for supplying a fluid heat exchange medium and a second passage through said shaft for returning said Inedium, and conduit means connecting said medium supply passage and medium return passage to a source of said heat exchange medium, characterized by said tubular blade means comprising an annular tube disposed coaxially with said shaft, an outer tube communicating with said return passage and with said annular tube, and an inner tube having nozzles and communicating with said supply passage and with said annular tube through said nozzles.

2. An agitator as claimed in claim 1, wherein said inner and outer tubes are disposed diametrically of said annular tube, said inner tube extending through said outer tube, and said nozzles are provided at either end of said inner tube within said annular tube and directed longitudinally thereof.

3. An agitator as claimed in claim 1, wherein said tubular blade means is provided with fins projecting from the outer surface thereof.

4. An agitator as claimed in claim 1, wherein said tubular blade means includes a plurality of annular tubes.

References Oitetl by the Examiner UNITED STATES PATENTS 1,417,037 5/1922 Cushman -86 1,458,321 6/1923 Bowman 165-87 X 1,667,944 5/1928 Nichols 16592 1,869,706 8/1932 Morrow 16592 1,962,803 6/1934 Bruins 16587 XR 2,025,651 12/1935 Dolan 165-142 X 2,042,979 6/1936 Anderson et a1 165-91 2,372,896 4/1945 Holm et al 165-142 X 2,680,007 6/1954 Arbuckle 16586 X 3,020,025 2/1962 OMara 165-142 X FOREIGN PATENTS 67,591 10/1957 France.

FREDERICK L. MATTESON, 1a., Primary Examiner. JAMES W. WESTHAVER, Examiner. 

1. A COMBINED AGITATOR AND HEAT EXCHANGER COMPRISING TUBULAR BLADE MEANS, A SHAFT, CONNECTING MEANS FOR SECURING THE BLADE MEANS TO THE SHAFT FOR ROTATION THEREWITH, DRIVING MEANS FOR ROTATING SAID SHAFT, A PASSAGE THROUGH SAID SHAFT FOR SUPPLYING A FLUID HEAT EXCHANGE MEDIUM AND A SECOND PASSAGE THROUGH SAID SHAFT FOR RETURNING SAID MEDIUM, AND CONDUIT MEANS CONNECTING SAID MEDIUM SUPPLY PASSAGE AND MEDIUM RETURN PASSAGE TO A SOURCE OF SAID 